U.S. Federal Reserve chair Jerome Powell reiterated the U.S. central bank plans to "wait and learn more" about the impact of tariffs on inflation before lowering interest rates, again setting aside President Donald Trump's demands for immediate and deep rate cuts.

"We're simply taking some time," Powell said at a central bank gathering in Portugal, a day after Trump sent him a handwritten missive noting how low other central banks had cut rates and suggesting the U.S. needed to move.

"As long as the U.S. economy is in solid shape, we think that the prudent thing to do is to wait and learn more and see what those effects might be," Powell continued.